A reflectance map may be used for accurately positioning a vehicle. Currently, a commonly used method for constructing a reflectance map of a region is as follows: a position output by a GPS device and an Euler angle output by an inertial navigation device when each frame laser point cloud is collected in the region are directly used as the position and Euler angle of the laser radar center when the each frame laser point cloud is collected, that is, used as the position and Euler angle of the laser radar center corresponding to the each frame laser point cloud. Coordinates, output by the laser radar, in a laser radar coordinate system of laser points in laser point cloud data corresponding to each frame laser point cloud are transformed by using the position output by the GPS device and the Euler angle output by the inertial navigation device when the each frame laser point cloud is collected, to obtain coordinates in a world coordinate system of the laser points in the each frame laser point cloud. Finally, each frame laser point cloud is merged according to the coordinates in the world coordinate system of the laser points in each frame laser point cloud to obtain a merged laser point cloud corresponding to the to-be-constructed reflectance map. The merged laser point cloud is then projected into a grid occupied by the region, and a mean and a variance of reflection strengths of laser points projected into each grid occupied by the region are calculated, to obtain map data of the reflectance map, so as to construct the reflectance map.
However, because the GPS device may be affected by factors such as satellite signal shifting, and the inertial navigation device may be affected by factors such as error accumulation, the position output by the GPS device and the Euler angle output by the inertial navigation device have large errors, and the coordinates, obtained after the transformation, of the laser points in each frame laser point cloud in the world coordinate system will also have large errors, leading to a reduction in the merging precision of the merged laser point cloud corresponding to the to-be-constructed reflectance map, and a reduction in the precision of the reflectance map.